And you just proved to all that you have no concept of common courtesy. Congratulations.
Now.. back on thread. There's a Honda dealership not far from my place, so I took a trip there just to see what's what. As stated, you can't get a locking gas cap for this generator. The reason is that there just isn't that big of a market for locking caps for generators, since most are used either for home power during an emergency or campground power in this size range. However, I had a look at the generator itself, and I think I could build a work-around to the problem of securing the gas cap quickly enough. There are places to secure your strap-metal, and if you do it right you can even make it look "factory"--- though I personally regard looks to be of lesser importance to keeping fiends from dumping foreign stuff into the tank.
I also like the idea of mounting the unit in a cage as has been suggested in this thread. The advantage being that you not only protect the fuel tank, you also help secure the entire unit from theft. Considering that this generator has a nearly 2K price tag, that's no small consideration.